Add functionality for LTM universal persistence profiles.

[retryW]

Is your feature request related to a problem? Please describe.

Currently the bigip terraform provider does not support universal persistence profiles. These are used in a number of locations within our environment, preventing us from moving these configurations into terraform.

Describe the solution you'd like

We would like to see universal persistence profiles added as a configurable terraform resource within this provider. They are already supported in the underlying go library used by this provider: https://github.com/f5devcentral/go-bigip/blob/859d6942bc8aa907d7d63233df030ca8d8a6830b/ltm.go#L535

Usage would be something along the lines of:

resource "bigip_ltm_persistence_profile_universal" "some_pp_universal" {
  name = "/Common/pp_universal"
  defaults_from = "/Common/universal"
  rule = "/Common/irule_sessionid"
  timeout = 180
}

Describe alternatives you've considered

Have not found any good alternatives

Additional context

This should be reasonably easy to implement as it is already supported in the underlying go library. The only non-standard persistence profile parameter in the schema would be for the specified irule, eg:

// Specific to UniversalPersistenceProfile
"rule": {
  Type:        schema.TypeString,
  Computed:    true,
  Optional:    true,
  Description: "The irule to use with this profile",
}